This present invention relates to an apparatus for candling eggs, i.e. to examine them by transparency, especially in order to select them according to whether they have been fertilised or not.
Once eggs from chickens, turkeys, pheasants or other poultry have been fertilised, the embryo and the ramifications of blood vessels being formed are rapidly visible by simple transparency. Sorting between fertilised and non-fertilised eggs can be performed visually, but automatic machines fulfilling this function have been developed for quite a long time.
These apparatuses comprise means enabling to determine the absorption factor of a light beam passing through the egg. When this absorption factor reaches a certain threshold, this reflects the presence of an embryo, the sign of fertilisation.
The apparatuses for candling eggs comprise a system transmitting a luminous flux intended to go through the egg, a device receiving the flux transmitted and means of computerised analysis of the signals recorded.
Each egg is analysed individually and the non-fertilised eggs are then put aside manually or automatically.
As a rule, the eggs are analysed directly in their incubation rack arranged horizontally on a conveying device. The transmission system and the reception device are arranged on the same vertical plane, one beneath the said conveying system and the other above the conveying system. The conveying characteristics of the incubation racks are suited to the type of transmitter and receiver used. The structure of these racks enables transparency analysis of the eggs in a vertical plane and the means of analysis used depend on the type or the different types of racks liable to be encountered.
During analysis, it may however happen that smears soil the portion of the device, which is situated beneath the conveying system, for example the transmission system of the luminous flux. These smears may originate from broken eggs, dusts or various waste and they are strongly detrimental to analysis quality.
The aim of the present invention is to overcome the above prior art inconvenience.
To this end, the invention relates to an apparatus for candling eggs of the type composed of a transmission system of a luminous flux directed towards the egg to be examined and located in its incubation rack, and of a device receiving the luminous flux transmitted after passing through the mass of the egg, associated with means of automatic analysis; the transmission system and the reception device are arranged in a vertical plane or a substantially vertical plane, one beneath the eggs to be examined and the other above the latter.
According to the invention, this apparatus comprises a screen protecting the transmission system or the reception device, against smears originating from the eggs or the incubation racks notably, by a gravity effect, which protection screen is made of an appropriate material so as not to disturb the luminous flux and which protection screen is associated with means of automatic cleaning.
According to a preferred embodiment, the transmission system of the luminous flux is placed beneath the eggs to be examined and the detection device above; the smears protection screen is placed between the eggs and the said transmission system.
According to another feature of the invention, the protection screen has the shape of a rotary cylinder in which are located the elements to be protected, and its external face is associated with means of automatic cleaning composed of means intended for the application of a cleaning agent and of a fixed scraping device.
According to another feature, the basis at least of the rotary protection cylinder is immersed in a tub filled with a cleaning agent in order to ensure application of a cleaning film on its external surface, under the action of its own rotation.
Still according to the invention, the protection cylinder is mounted on a fixed axle via lateral flanges, whereas the assembly of the cylinder on the flanges and the assembly of the said flanges on the fixed axle are made watertight. The fixed axle serves advantageously as a support for the elements to be protected, whereas the power supply and the control means of the latter pass through the said axle.
According to another feature, the apparatus comprises means of automatic and continuous conveying of the racks of eggs to be analysed and the protection cylinder is brought into rotation by the driving system of the said conveying means, via a mechanical transmission unit.
Still according to the invention, the apparatus comprises a luminous flux transmission system composed of one or several infrared cells and a camera-type detection system, provided with an infrared filter.
Preferably, a series of transmission systems are adapted to transmit several luminous fluxes, each oriented towards one of the eggs of a given row to be analysed simultaneously and a single detection camera scans the whole corresponding row, to record, then to enable analysing, the luminous fluxes transmitted.
According to another feature, the apparatus comprises a motorised inlet conveyor and a motorised outlet conveyor, between which is placed a supporting tray provided with orifices opposite each egg of the same row, enabling the luminous flux to come through.